Plasterer&#39;s center ribbed aluminum darby



July 21, 1936. A. s. WILLIAMS 2,048,529

PLASTERERS CENTER RIBBED ALUMINUM DARBY Filed Oct. 17, 1955 mi E' I Am aMW/ mf Patented July 21. 1936 1 'UNITED STATE/S,

PLASTERERS CENTER RIBED, UMINUM" I g This invention has generalreference to improvements in plasterers darbies; and it consists,essentially, in the novel and peculiar combination of parts and detailsof construction, as '5 hereinafter first fully set forth and described,and

thenpointedout in the claims.

I The principal object of this invention is to provide a darby whereinthe blade of the darby consists of a flat strip of aluminum that is re-10 inforced by a wood rib arranged on the aluminum strip along thelongitudinal center line thereof. v

Another object of the invention relates to a metallic reinforcement forthe wood rib torex- 15 tend the full length thereof. v a

A further object of the invention resides in the manner of mounting thehandle; and fin of the darby on thewood rib. v

A still further object of the'invention relates 2Q to the roughening orfluting of the longitudinal edges of the aluminum blade of the darby toprovide a proper key for the finishing coat of plaster.

With the foregoing and other objects in view 25 which will appear as thedescription proceeds, it is. to be understood that changes in theprecise embodiment of the invention herein disclosed may be-made withinthe scope of what is claimed without departing from the spirit of theinven- 30 tion.

In the accompanying drawing the preferred form of the invention has beenshown.

In said drawing: Figure 1 is a perspective view of the improved 35plasterers darby,

Figure 2 is a cross-sectional view thereof taken on line 2-2, Figure 1,

Figure 3 is a cross-sectional view thereof taken on line 3-3, Figure 1,40 Figure 4 is a perspective view of a portion of one edge of the darbyblade showing the transverse serrations or grooves thereon, and

Figure 5 is an end elevational view showing the longitudinal grooves orflutings on the underface of the blade.

Referring again to the drawing, the darby shown in its entirety inFigure 1, comprises the usual blade H) which in this case is preferablymade of a strip of aluminum or other suitable 50 preferably non-ferrousmetal having a thickness of A a width of 3%" and a length of 40". Thesedimensions have been found most satisfactory for general use of a darbythough it is obvious that the blade thereof may assume 55 otherdimensions if so desired. The metallic blade I0. is fiat throughoutitsentire extent'and of rectangular formation with the longitudinaledges H and [2 parallel.

jDisp'osedon one side l3 of the blade l along the, longitudinal centerthereof is a wood rib l4,

the 'ends'of which terminate short of the transverse edges of the bladevIt] as clearly shownin Figure 1. Encasing the wood rib [4 whichpreferably is of square. cross-section" is a metallic channelreinforcement li that is adapted to snuel0 ly receive the wood'rib M..The legs or sides I6 of the channel. [5 are of a'length less than theheight of the wood rib so that the same are spaceda slight distance fromthe surface l3 o'f-the'blade ii], for a 'purposeto be hereinafterdescribed. The channel? I5 is preferably made of aluminum or'otherlnon-ferrous metal, of rolled or cast stock andiof not less thanthickness throughout.

- 'The blade' I, wood rib. l4; and metallic chanher I'5'are securedrigidly together by the spaced screws or rivets I8.

. Adjacent one end: of thejblade l0 is arranged an upright wood" handle20'that. is preferably seated on the channel l5 and rigidly secured inplace: byfthe' screw '21, that passes upwardly thro'iighthe fbl'ade I 0,wood rib '14; channel l5 into threaded engagementwitha threaded metallicbushing 22 provided axially within" the handle '20 all as clearly shownin Figure3. If desired the wood handle 20 may be replaced with ametallic handle in which case the bushing 22 may be replaced with athreaded bore within the handle.

Also adjacent the other end of the blade I0 is arranged a fin 25 of woodor metal seated on the channel I5 and rigidly secured in place in thesame manner as the handle 20 is secured in place.

The rivets or screws l8 and the screws 2| are provided with counter-sunkheads that are flush With the under surface of the blade l0, and arealso made of a non-ferrous metal to obviate any corrosion taking place.

The longitudinal edges II and I2 of the blade 745 ID are roughened,vertically serrated or grooved as indicated by the reference character21 so as to provide when the darby is used on. the first brown coat ofmortar a'proper key thereon for the application of the second or whitecoat of plaster. In Figure 4, the vertical'grooves 21' along the edgesof the darby blade are formed by pressing the same in with a suitabletool with a consequent deformation of the metal at the ends of thegrooves and edges of the darby as at "28 As these raised portions 28wear off in use there' will still be left the grooves 21' to provide theproper key. If desired the roughened edge or vertical serrations may bedispensed with entirely and small grooves or flutes 29, see Figure provided on the under face of the blade ashort distance from each of theedges II and I2; This the first plaster coat.

is anothermethod for accomplishingthe same purpose for the provision of'the proper key on I I desire it understood however each of the aboveindicated keying means are not strictly necessary to the operation ofthe derby) as the same may in the'hands of a' skillful plasterer be usedsuccessfully; In some cases the edges of a the blade I]! mayjbe suppliedtrueeandismooth' in the manufacture thereof and the sameioughened by theplastererf'if s'o'desired, by merely hacking the edges with .theplasterers pointing trowel whichhe has at hand at all times. This willin no v way affect the durability of thefdarby.

'f The invention as above'set forth has theadvantageover a wood darby ora wood darby pro lvided withrmetlallic edges in that by virtue of thealuminum blade employed thesam'e will not hang to the mortar with'theconsequent pulling off of the mortar; the aluminum blade sliding overthe rmortar with greatergease as well'as acting to fill finall-'unevenfportions. 'Anotheradvantage of the invention relates to thefact that the'darby may be manipulated without ajsprinklin'g 'of wa t'eron the plaster or mortar as is done beforeusing a'wood darby; the useofwater acting to 'd'estroy'the hardness of the'surface 'of'the plaster orImortarlto someextenti Therdarby of this invention retainsat alltimes'apermanent straighthess when applied against the plaster in thenatrural position by being held by the handle and fin.

. Atthe same time it can be'fiexed by the application of" the properpressure to the handle and Vfin. "It'is' evident that because the wallsIt of the channel l5 are. clear of the upperjsurface 13 of th'elblade10, the reinforced rib "construction will permitof, this flexing of thedarby. I 'Inasmuch as the handle and fin are secured to the wood rib andchannel there is no, dangerv of the same pulling away or turningon thecompara- 7 means for rigidly --securing said fblade; crib and handlingmeans together.

Having thus set forth and disclosed the nature of thisinvention, what isclaimed is: V

1. A darby comprising a single elongated fla blade of non-ferrous metal,a rib extending substantially the full length of said blade terminat- 5ing short of the ends thereof and positioned thereon along thelongitudinal. axis 7 thereof, spaced handling means arranged on the ribadjacent the ends thereof, and? comn ongf astening 12. A darbycomprising an elongated flat blade of non-ferrous'metal, a wood'rib'extending sub' 'stantially thefull'length of said bladeand arranged onthe longitudinal axis thereof, reinforce ing means for said wood rib,spaced handling means arranged von the rib adjacent, th'e'ends thereof;and common'fastening means for rigidly securing said blade, wood rib,reinforcing and handling means togethern 3. In the-"darby as; set manatem 2; said,

reinforcing means comprising a' non-ferrous me-V tallic channel snug'l'yembracing said wood; rib 7 over itsentire length the legs 'ofsaidchannelbeing of {a length less thanthe height-ofsaid rib and spaced fromtheupper face ofsaid blade and separate spaced fastening means for rigidly"V securing together said blade, wood rib and chan nel reinforcement.-

" 4: In the 'darby asset forth 'in -cl airn' 2,-said spaced handling:means} comprising ahandle at one end of said darby and an elongatedmi-at the otheriend thereof: I o

' '5. In'the darby as' set'forth in 'claimfl, the a longitudinal edgesof said'bladebeing roughened V or serratedwfl' a i 6. In the-'darby asset rqr'mm claim 2, the V longitudinal edges of said blade beingroughened or serrated. '7 5 Y f I 7; In thedarbyras setlforth in claim1', anda plurality of longitudinal grooves or flutes fprovidedonthe'under face of said bladeadjacent' j the longitudinal edges thereof.*q I V 8. In the darby as set forth in 'claim2,"and' grooves or; flutesprovided' on V the under face' of said blade adjacent the longitudinal'edgesithere

